Device for guiding and putting under tension a band of a sliding fastener

ABSTRACT

Device for guiding and putting under tension a band, such as a band of a sliding fastener, in the course of the stitching of the band to a workpiece. The device comprises a bridge adapted to be fixed to a sewing machine in the vicinity of the stitching part of the machine, a spring strip for pressing the band against an upper wall portion of the bridge and means for progressively regulating the pressure exerted by the spring strip on the band.

1Inited States Patent 1191 Lacam May 14, 1974 [54] DEVICE FOR GUIDING AND PUTTING 2,977,904 4/1961 Carmen 112/105 UNDER TENSION ABAND OF A SLIDING 2,761,401 9/1956 Dolney 112/152 Filed:

F ASTENIER Inventor: Guy S. P. Lacam, Paris, France La Fermeture Ailee, Airaines, France Appl. No.: 187,437

Assignee:

Foreign Application Priority Data Oct. 12, 1970 France 70.36747 Aug. 11, 1971 France 70.29337 US. Cl. 112/152 Int. Cl D051) 35/06 Field of Search 112/265, 266, 136, 137, 112/138, 5052,14l,147, ISO-153,105, 121.26, 121.27

References Cited UNITED'STATES PATENTS Kellum 112/136 Primary Examiner-Jordan Franklin Assistant ExaminerPeter Nerbien Attorney, Agent, or Firm Burns, Doane, Swecker and Mathis [57] ABSTRACT machine in the vicinity of the stitching part 'of the machine, a spring strip for pressing the band against an upper wall portion of the bridge and means for progressively regulating the pressure exerted by the spring strip on the band.

13 Claims, 6 Drawing Figures- PATENTEDHAY 14 1974 SHEET 3 OF 3 The present invention relates to the fixing of flexible bands, and in particular bands of a sliding fastener, to

a workpiece such as a piece of clothing.

[t is now usual practice to sew onto the workpieces portions of bands, for example finished bands of sliding fasteners, which are provided with a slider and lower or upper stops of the like and are driven along by the workpiece and advance as they are stitched to the workpiece and furthermore to employ bands on a bobbin which are unwound continuously as this stitching proceeds. Experience has shown that in either case a regular sliding of a band is difficult to achieve even if the latter is guided between two longitudinal abutment surfaces.

Indeed, depending on the nature of the two materials employed, that is, the materials of the workpiece and band, and in particular depending on their coefficients of friction, experience has shown that the advance of the band is not strictly synchronous with that of the workpiece whose advance is ensured automatically by the claws or other driving means provided on the sewing machine which interconnects the band and the workpiece.

lt often occurs that the. workpiece folds with respect to the band or, inversely, that the latter moves too quickly and forms waves or corrugations which have an adverse effect on the correct stitching of the band to the workpiece.

Devices have already been proposed for both guiding and putting the band to be sewn under tension so as to remedy the aforementioned drawback.

But these devices are complicated to use and are usually large in size so that it is difficult to adapt them to a sewing machine where the available space is limited, above all if it is desired to avoid hindering the correct feed of the workpiece. Moreover, the results are disappointing.

An object of the invention is to provide a device for guiding and puttingunder tension a band, and in particular a band of a sliding fastener, in the course of the stitching of the band to a workpiece, which completely avoids the drawbacks of an irregular unwinding of the band and/or the workpiece and thus achieves an even jerk-free stitching of the band to the workpiece.

The invention provides a device comprising an element constituting a bridge and adapted to be fixed to a sewing machinein the vicinity of the stitching point, a resiliently yieldable strip for pressing the band to be sewn against the bridge, the band passing between the strip and the bridge, and micrometric means for progressively regulating the pressure exerted by the strip on the band.

By means of these micrometric regulating means, the operator is able at each instant to exactly regulate the tension ofthe band which is moreover normally guided by the lateral faces of the bridge.

According to another feature of the invention, the bridge has in its upper wall portion a throughway longitudinally extending slot located above the median part of the strip.

This slot permits supervising the sliding of the band which can therefore be corrected immediately as soon as an incident occurs. It also permits the passage of the sliders, the lower or upper stops or other means projecting from the band, so that the device can be employed for the fixing of any type of sliding fasteners or the like.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings.

In the drawings:

FIG. l is a perspective view of a device according to the invention;-

FIG. 2 is a similar view with a part cut away;

FIG. 3 is a perspective view, with a part cut away, of a modification of the device for putting a band under tension;

FIG. 4 is a sectional view taken along line 44 of F IG. 3, and

H6. 5 is a detail perspective view showing the form of the band tension regulating cam, and

FIG. 6 is a sectional view taken along line 6-6 of FIG. 3.

According to the illustrated embodiment, the device according to the invention is employed for simultaneously stitching toa piece of fabric or thelike, constituting the workpiece, two bands 1 and l constituting the two elements ofa sliding fastener, these bands having on their adjacent longitudinal edge portions hooking elements 2 adapted to be hooked together and unhooked from-each other by means of a slider of known type (notshown in the drawing).

The two linesof stitching necessary for securing the two bands to the workpiece are produced by two needles 3 of a sewing machine. These needles have reciprocating longitudinal movements and extend into apertures 4 in a needle plate 5 and cooperate with loop takers disposed below the platform of the machine.

The device for guiding the band and putting it under tension is arranged in such manner as to be capable of being placed on the upstream side of the needle plate 5 with respect to the direction of movement of the workpiece (indicated by arrow f).

This device comprises a main element constituting a bridge 6 which has a mainly H-shape in plan. Screws 7 connect the bridge 6 to a base 8 having the same shape and constituting a stand. This base8 is provided with two longitudinal rabbets 8a whose horizontal flanges constitute slides adapted to slide in the opening of the machine which is provided in the platform for normally receiving the slide of the machine.

Owing to the arrangement of the base 8, which takes the place of the usual slide on the sewing machine, the sewing machine accessory constituted by the device can be very easily fixed to. or removed from the machine when the machine is to be used for other purposes.

Adjacent the rear, that is, adjacent the upstream end with respect to the direction of movement of the workpiece, the base 8 has a reduced thickness so that it can purely and simply rest against the platform of the sewing machine with the bridge 6 perfectly horizontal.

This bridge 6 has a U-shaped cross section and it defines above the base 8 a passage 9 having a flat rectangular-shaped section. This passage 9 communicates with the upper face of the bridge by way ofa longitudinal slot 10 provided for viewing the interior of the mechanism and possibly cleaning it in the case ofjamming with threads, hairs or dust. This slot also enables the operator to supervise the unrolling of the sliding fastener and intervene with a suitable tool in the event of a jamming of the fastener.

The slot may be closed at both ends as shown in FIGS. 1 and 2 and merely serve to supervise the interior of the mechanism and the unwinding of the band or may be open at both ends as shown in FIG. 3 so as to allow the passage of a slider, or a lower or upper stop of the sliding fastener or any other element which projects from the band.

inside the longitudinal passage 9 thus defined under the bridge 6 there is disposed a resiliently yieldable strip 11 which extends throughout the length of the bridge and is secured at the rear on the base 8 by two screws or rivets l2 and extends out of the passage 9 at the other end of the base 8. The strip 11 has a median longitudinal recess 13 adapted to define a free passage for projections on the fastener formed by the hooking elements 2 and may cooperate with the slot 10 with which it is parallel and coaxial.

The device is completed by means for very progressively regulating the position of the strip relative to the upper wall of the passage of the bridge 6.

These means are constituted by a micrometric screw 14 (FlG. 2) which is screwed in a tapped hole 15 formed in a boss 16 which extends from the lower face of the base 8. Secured on the upper portion of this screw 14, or an integral part thereof, is an end head 17 which is engaged in the complementary part of a knurled disc 18 and is in contact with the lower face of the strip 11. The screwing of the screw 14 shifts the head 17 and causes it to raise the strip 1] which moves closer to the bridge 6 and reduces the free passage allowed for the band. On the other hand, the unscrewing of the screw 14 releases this strip 11 which moves awa from the bridge 6 owing to its resilience.

The disc 18 has such diameter that it extends beyond the middle longitudinal portion of the bridge 6 and it is possible to rotate the disc manually on either side and thus regulate the gap between the upper face of the strip 11 and the lower face of the upper wall of the passage 9. This disc has graduations which enable the operator of the sewing machine to set the exact position of the micrometer screw 18 and in-particular the position of the head 17 by bringing one of the graduations in front of an index or reference mark 19 carried by the bridge.

The device according to the invention operates in the following manner:

The fastener to be sewn is engaged longitudinally in the passage 9 of the bridge between the upper wall of the passage and the strip 11. By rotating the disc 18, the position of the strip ll is adjusted so as to exert a suitable pressure on the fastener.

In the course of stitching, the usual driving claw of the sewing machie drives the workpiece in the direction of arrow 1 and the workpiece pulls through the already sewn portion of the fastener which unwinds from the left side of the illustrated device. The regulation of the position of the strip ll, on which it is possible to act very progressively by means of the micrometer screw 14, enables the required tension to be given to the band so that it unrolls exactly in synchromism with the feed of the workpiece with no formation of folds or corrugations on either of the elements.

At any moment, and in particular in case of an incident, it is possible to modify this regulation by a very progressive action on the disc and thus correct the pressure exerted by the strip 1] on the band either by moving it nearer to the bridge by screwing the screw 14 or by allowing it to move away from the bridge by unscrewing the screw 14.

It must be understood that the illustrated embodiment is not intended to be exclusive. The micrometer screw 14 and its disc 18 may be replaced by any other micrometric means acting in a similar or like manner on the strip, for example by a cam provided with a relatively long lever as shown in FIG. 3.

In this case, a plate 22, fixed to the lower part of the base 8, supports a boss 24 which defines two helical semi-ramps 26, 27 (FIG. 5). Above these ramps there is a cam 28 which also has two helical semi-ramps and is integral with a disc 30 which extends beyond the bridge 6 and is secured to a shifting lever 31.

The shifting of the lever 31 causes the cam 28 to slide over the helical ramps 27, 26 and thus results in a vertical displacement of the disc 30. The latter bears against the lower face of the strip 11 and causes it to move nearer to the upper wall of the bridge 6. When the disc 30 is moved downwardly the resilience of the strip 11 tends to move the strip away from the bridge.

Preferably, the strip 11 is not plane but has at 33 at its end opposed to the fixing screws 12 a slightly curved shape the convexity of which faces the upper wall of the bridge 6. The displacement of the cam 28 or the micrometer screw 14 raises the center portion of the strip 11 and causes this convex portion 33 to be clamped to a variable extent against the bridge and adjusts in this part the dimension of the passage for the band and consequently the tension of the latter.

According to a modification shown in FIG. 3, the strip 11 is provided substantially in the region of the convex portion 33 with two lateral ear portions supporting in their lower part studs or a transverse bar 32 which has a longitudinal lateral notch 34 in which is engaged one of the sides of an arm or flat lever 36 disposed in a recess 38 in the base 8.

The bar 32 is movable in a cavity in the base 8 and in a corresponding cavity provided in the bridge 6 so that it is free to move to a variable depth into the base 8. Further. the arm 36 is integral with a shifting handle 40 which is located outside the device and forms with the arm 36 a crank.

The position of the arm 36 is such that at rest it is substantially horizontal in the recess 38 and is free inside the notch 34. As the height of the notch is greater than the thickness of the arm 36, the bar 32 can be displaced vertically by regulating means so as to put the band under tension without modification of the position of the arm. On the other hand, when the handle 40 of the lever 36 tilts, one of its sides abuts the bridge 6 whereas the other causes the bar 32 to move into the base 8. The strip 11 is moved downwardly and separated from the upper wall of the bridge 6 and allows the free passage of the band between the bridge and the strip 11.

As soon as the handle 40 is released, the resiliently yieldable strip 11 resumes its curved shape and the position corresponding to the setting determined by the disc 30 or l8.

Thus it is possible to give to the regulating means a given position corresponding to the nature of the band and of the workpiece and to introduce in succession portions of band to be fitted to different parts of the workpiece without modifying this regulation, simply by presser foot of the sewing machine.

acting on the lever 40 so as to permit the introduction of each portion and then the desired putting under tension.

It will be understood that at any time the unwinding of the band may be easily supervised through the slot and the regulation can be carried out if an incident occurs, for example if corrugations are formed in the band or the workpiece.

Such a device can be employed for fixing any band irrespective of the material of which it is constituted and in particular any sliding fastener which is continuous or discontinuous, provided,or not provided with a slider or a hooking or any other projecting means.

The regulation of the micrometer screw permits easy adaptation to the thickness of this band and the dimensions of the passage 9 and of the bridge itself can be adapted to the width of the band.

Further, although the illustrated arrangement is of particular interest owing to the ease with which it is installed and the small extent of its, projection from the platform, the device according to the invention can if desired occupy any other position, in particular if the band or bands must be sewn to the upper face of a workpiece and not to the lower face thereof as in the illustrated embodiment. The base 8 indeed has two apertures which allow its fixing at a point of the sewing machine, for example on the end head of the arm projecting from this sewing machine, the band being in this case fed by the guide in the immediate vicinity of the Such a device has an extremely small height and does not hinder the feed of the workpiece which can cover it partially or completely and through which the operator can with his hand turn,if desired,in one direction or the other and by small movements the disc 18 integral with the micrometer screw 14.

Having now described my invention what I claim and desire to secure by Letters Patent is 1. In a guide device for guiding in a given direction and putting under tension a band in the course of the stitching to a workpiece, means defining a bridge having a base for attachment to a sewing machine platform in the vicinity of the stitching part of the sewing machine, said base including lateral L-shaped slide portions adaptably engaged with said platform, said bridge having an upper wall portion, a resiliently yieldable strip secured to said bridge, said strip being parallel to a given direction defining with said bridge a longitudinal passage for guiding said band in said .given direction, said resiliently yieldable strip constituting a lower portion of the passage and extending throughout the length of the passage and beyond each end of the passage, said strip exerting a resiliently yieldable force in the direction of said upper wall portion, so that said strip presses said band against said upper wall portion, said band adapted to pass between said strip and said upper wall portion and means associated with said strip for progressively regulating said force exerted by said stri In the device claimed in claim 1, a longitudinal slot formed in and extending throughout the thickness of said upper wall above a median portion of said strip.

3. ln the device claimed in claim I, said resiliently yieldable strip having a rearportion, with respect to the direction of feed of the band, and including a longitudinally extending median portion and a longitudinal re- 6 cess in said median portion for clearing projecting elements on said band.

4. In a device claimed in claim 1, said means associated with aresiliently yieldable strip comprising a screw adapted to be screwthreadedly engaged with said base said screw being in contact with a face of said strip remote from said upper wall portion for progressively regulating said force exerted by said strip by rotation of said screw relative to said base. I

5. In the device claimed in claim 4, said means associated with said strip further including a disc extending laterally beyond said bridge and means drivingly connecting said disc to said screw for rotating said screw.

6. In a device for guiding in a given direction and putting under tension a band in the course of the stitching of the band to a workpiece means defining a bridge having a base for attachment to a sewing machine in the vicinity of the stitching part of the sewing machine, said bridge having an upper wall portion, a resiliently yieldable strip for exerting a resiliently yieldable force in the direction of said upper wall portion so as to press said band 'againstsaid upper wall portion, said band adapted to pass between said strip and said upper wall portion, regulatingmeans comprising a rotatable member engaging a face of said strip remote from said upper wall portion and cooperable with said base, cam means interposed between said member and said base and an actuating lever extending beyond said bridge and connected to said rotatable member for rotating said member whereby said member progressively regulates said force exerted by said strip.

7. In the device claimed in claim 1, said strip having a curved end portion having a convexity facing said upper wall portion and said regulating means being in contact with a portion of said strip at a slight distance from said portion, said strip having an end portion which is remote from said curved portion and is held in position relative to said bridge.

8. In a device for guiding in a given direction and putting undertension a band in the course of the stitching of the band a workpiece means defining a bridge having a base for attachment to a sewing machine in the vicinity of the stitching part of the sewing machine, said bridge having an upper wall portion, a resiliently yieldable strip for exerting a resiliently yieldable force in the direction of said upper wall portion so as to press said band against said upper wall portion, said band adapted to pass between said strip and said upper wall portion, regulating means associated with said strip for progressively regulating said force exerted by said strip, and separating means for separating said strip from said upper wall portion and stopping the pressing action of said strip without modification of said regulating means.

9. In the device claimed in claim 8, said separating means comprising a projecting portion integral with a lower part of said strip, a notch in said projecting portion, a lever pivotablerelative to said bridge and engaged in said notch and pivotable between an upper position of rest allowing the raising of said strip for pressing said band against said upper wall portion and a lower position in which said strip is moved away from said upper wall portion.

10. In the device claimed in claim 9, said pivotable lever having an arm portion-extended by an actuating handle and a second arm portion having a first portion engaged in said notch, said base having a recess and l3. ln the device claimed in claim 1, said base having a part which is a rear part relative to the direction of feed of said band and is thinner than a front part of said base and said lateral sliding parts being provided in said front part so that when said front part is engaged with a sewing machine platform, said rear part merely bears against said platform. 

1. In a guide device for guiding in a given direction and putting under tension a band in the course of the stitching to a workpiece, means defining a bridge having a base for attachment to a sewing machine platform in the vicinity of the stitching part of the sewing machine, said base including lateral L-shaped slide portions adaptably engaged with said platform, said bridge having an upper wall portion, a resiliently yieldable strip secured to said bridge, said strip being parallel to a given direction defining with said bridge a longitudinal passage for guiding said band in said given direction, said resiliently yieldable strip constituting a lower portion of the passage and extending throughout the length of the passage and beyond each end of the passage, said strip exerting a resiliently yieldable force in the direction of said upper wall portion, so that said strip presses said band against said upper wall portion, said band adapted to pass between said strip and said upper wall portion and means associated with said strip for progressively regulating said force exerted by said strip.
 2. In the device claimed in claim 1, a longitudinal slot formed in and extending throughout the thickness of said upper wall above a median portion of said strip.
 3. In the device claimed in claim 1, said resiliently yieldable strip having a rear portion, with respect to the direction of feed of the band, and including a longitudinally extending median portion and a longitudinal recess in said median portion for clearing projecting elements on said band.
 4. In a device claimed in claim 1, said means associated with a resiliently yieldable strip comprising a screw adapted to be screwthreadedly engaged with said base said screw being in contact with a face of said strip remote from said upper wall portion for progressively regulating said force exerted by said strip by rotation of said screw relative to said base.
 5. In the device claimed in claim 4, said means associated with said strip further including a disc extending laterally beyond said bridge and means drivingly connecting said disc to said screw for rotating said screw.
 6. In a device for guiding in a given direction and putting under tension a band in the course of the stitching of the band to a workpiece : means defining a bridge having a base for attachment to a sewing machine in the vicinity of the stitching part of the sewing machine, said bridge having an upper wall portion, a resiliently yieldable strip for exerting a resiliently yieldable force in the direction of said upper wall portion so as to press said band against said upper wall portion, said band adapted to pass between said strip and said upper wall portion, regulating means comprising a rotatable member engaging a face of said strip remote from said upper wall portion and cooperable with said base, cam means interposed between said member and said base and an actuating lever extending beyond said bridge and connected to said rotatable member for rotating said member whereby said member progressively regulates said force exerted by said strip.
 7. In the device claimed in claim 1, said strip having a curved end portion having a convexity facing said upper wall portion and said regulating means being in contact with a portion of said strip at a slight distance from said portion, said strip having an end portion which is remote from said curved portion and is held in position relative to said bridge.
 8. In a device for guiding in a given direction and putting under tension a band in the course of the stitching of the band a workpiece : means defining a bridge having a base for attachment to a sewing machine in the vicinity of the stitching part of the sewing machine, said bridge having an upper wall portion, a resiliently yieldable strip for exerting a resiliently yieldable force in the direction of said upper wall portion so as to press said band against said upper wall portion, said band adapted to pass between said strip and said upper wall portion, regulating means associated with said strip for progressively regulating said force exerted by said strip, and separating means for separating said strip from said upper wall portion and stopping the pressing action of said strip without modification of said regulating means.
 9. In the device claimed in claim 8, said separating means comprising a projecting portion integral with a lower part of said strip, a notch in said projecting portion, a lever pivotable relative to said bridge and engaged in said notch and pivotable between an upper position of rest allowing the raising of said strip for pressing said band against said upper wall portion and a lower position in which said strip is moved away from said upper wall portion.
 10. In the device claimed in claim 9, said pivotable lever having an arm portion extended by an actuating handle and a second arm portion having a first portion engaged in said notch, said base having a recess and said second arm portion having a second portion pivotably engaged in said recess.
 11. In the device claimed in claim 9, said bridge and said base having facing cavities for accommodating said projecting portion and the movements of said projecting portion.
 12. In the device claimed in claim 10, said second portion being locked in said recess and said first portion being pivotable in said notch.
 13. In the device claimed in claim 1, said base having a part which is a rear part relative to the direction of feed of said band and is thinner than a front part of said base and said lateral sliding parts being provided in said front part so that when said front part is engaged with a sewing machine platform, said rear part merely bears against said platform. 